London (new series) v, p. 220 (1878)), while spicules, a.s.signed by Ehrenberg to various genera but actually those of _Spongilla lacustris_ or allied forms, have been found in the Miocene of Bohemia (see Ehrenberg's 'Atlas fur Micro-Geologie,' pl. xi (Leipzig, 1854), and Traxler in Foldt. Kozl., Budapest, 1895, p. 211). _Ephydatia_ is also known in a fossil condition, but is probably less ancient than _Spongilla_.

Ehrenberg found many sponge spicules in earth from various parts of the Indian Empire (including Baluchistan, Mangalore, Calcutta, the Nicobars and Nepal) and elsewhere, and it might be possible to guess at the ident.i.ty of some of the more conspicuous species figured in his 'Atlas.'

The identification of sponges from isolated spicules is, however, always a matter of doubt, and in some cases Ehrenberg probably a.s.signed spicules belonging to entirely different families or even orders to the same genus, while he frequently attributed the different spicules of the same species to different genera. Among his fossil (or supposed fossil) genera that may be a.s.signed to the Spongillidae wholly or in part are _Aphidiscus_, _Spongolithis_, _Lithastericus_ and _Lithosphaeridium_, many of the species of these "genera" certainly belonging to _Spongilla_ and _Ephydatia_.

ORIENTAL SPONGILLIDae NOT YET FOUND IN INDIA.

Few freshwater sponges that have not been found in India are as yet known from the Oriental Region, and there is positive as well as negative evidence that Spongillidae are less abundant in Malaysia than in this country. The following list includes the names of those that have been found, with notes regarding each species. It is quite possible that any one of them may be found at any time within the geographical boundaries laid down for this 'Fauna.' I have examined types or co-types in all cases except that of _Ephydatia fortis_, Weltner.

I. _Spongilla_ (_Euspongilla_) _microsclerifera_*, Annandale (Philippines). P. U.S. Mus. x.x.xvii, p. 131 (1909).

This sponge is closely related to _S. lacustris_, but apparently does not produce branches. It is remarkable for the enormous number of microscleres in its parenchyma.

II. _S._ (_Euspongilla_) _philippinensis_*, Annandale (Philippines). P.

U.S. Mus. x.x.xvi, p. 629 (1909).

Related to _S. alba_ and still more closely to _S. sceptrioides_ of Australia. From the former it is readily distinguished by having minutely spined megascleres, green corpuscles, slender gemmule-spicules with short spines and no free microscleres.

III. _S._ (? _Euspongilla_) _yunnanensis_*, Annandale (W. China). Rec.

Ind. Mus. v, p. 197 (1910).

Apparently allied to _S. philippinensis_ but with smooth skeleton-spicules and a more delicate skeleton.

IV. _S._ (_Stratospongilla_) _sinensis_*, Annandale (Foochow, China). P.

U.S. Mus. x.x.xviii, p. 183 (1910).

This species and _S. clementis_ are referred to _Stratospongilla_ with some doubt. Their gemmules are intermediate in structure between those of that subgenus and those of _Euspongilla_. In _S. sinensis_ the gemmules are packed together in groups at the base of the sponge, and their spicules are smooth, stout, and gradually pointed.

V. _S._ (_Stratospongilla_) _clementis_*, Annandale (Philippines). P.

U.S. Mus. x.x.xvi, p. 631 (1909).

The gemmules are single and closely adherent at the base of the sponge.

Their spicules are very slender and minutely spined.

VI. _S._ (? _Stratospongilla_) _coggini_*, Annandale (W. China). Rec.

Ind. Mus. v, p. 198 (1910).

The gemmules apparently lack microscleres. They resemble those of _S.

clementis_, to which the species is probably related, in other respects.

The skeleton-spicules are spiny and rather stout, the species being strongly developed at the two ends.

VII. _S._ (_Stratospongilla_) _sumatrana_*, Weber (Malay Archipelago).

Zool. Ergebnisse einer Reise in Niederlandisch Ost-Indien, i. p. 38 (1890).

Closely allied to _S. indica_ (p. 100) but with pointed skeleton-spicules.

VIII. _Ephydatia fortis_, Weltner (Philippines). Arch. Naturgesch.

lxi(i), p. 141 (1895).

This species is remarkable for the great development of the spines on the shaft of the gemmule-spicules.

IX. _Ephydatia bogorensis_*, Weber (Malay Archipelago). Zool. Ergebnisse einer Reise in Niederlandisch Ost-Indien, i, p. 33 (1890).

The gemmule-spicules have rather narrow flattish disks, the edge of which is feebly but closely serrated.

X. _E. blembingia_*, Evans (Malay Peninsula). Q. J. Microsc. Sci.

London, xliv, p. 81 (1901).

The gemmules resemble those of _Dosilia plumosa_ but are spherical.

There are no free microscleres.

XI. _Tubella vesparium_*, v. Martens (Borneo). Arch. Naturg.

Berlin, x.x.xiv, p. 62 (1868).

Closely related to _T. vesparioides_ (p. 189), but with spiny megascleres.

As regards _Spongilla decipiens_*, Weber, from the Malay Archipelago, see p. 97.

II.

HISTORY OF THE STUDY OF FRESHWATER SPONGES.

The bath-sponge was known to the Greeks at an early date, and Homer refers to it as being used for cleansing furniture, for expunging writing, and for ablutionary purposes. He also mentions its peculiar structure, "with many holes." "Many things besides," wrote the English naturalist Ray in his 'Historia Plantarum' (1686), "regarding the powers and uses of sponges have the Ancients: to them refer." Ray himself describes at least one freshwater species, which had been found in an English river, and refers to what may be another as having been brought from America. In the eighteenth century Linne, Pallas and other authors described the commoner European Spongillidae in general terms, sometimes as plants and sometimes as animals, more usually as zoophytes or "plant-animals" partaking of the nature of both kingdoms. The gemmules were noted and referred to as seeds. The early naturalists of the Linnaean Epoch, however, added little to the general knowledge of the Spongillidae, being occupied with theory in which theological disputes were involved rather than actual observation, and, notwithstanding the fact that the animal nature of sponges was clearly demonstrated by Ellis[U] in 1765, it was not until the nineteenth century was well advanced that zoologists could regard sponges in anything like an impartial manner.

[Footnote U: Phil. Trans. Roy. Soc. lv, p. 280.]

One of the pioneers in the scientific study of the freshwater forms was the late Dr. H. J. Carter, who commenced his investigations, and carried out a great part of them, in Bombay with little of the apparatus now considered necessary, and with a microscope that must have been grossly defective according to modern ideas. His long series of papers (1848-1887) published in the 'Annals and Magazine of Natural History' is an enduring monument to Indian zoology, and forms the best possible introduction to the study of the Spongillidae. Even his earlier mistakes are instructive, for they are due not so much to actual errors in observation as to a faithful transcription of what was observed with faulty apparatus.

Contemporary with Carter were two authors whose monographs on the freshwater sponges did much to advance the study of the group, namely, J. S. Bowerbank, whose account of the species known at the time was published in the 'Proceedings of the Zoological Society of London' in 1882, and the veteran American naturalist Mr. Edward Potts, whose study of the freshwater sponges culminated in his monograph published in the 'Proceedings of the Academy of Natural Sciences of Philadelphia' in 1887. Carter's own revision of the group was published in the 'Annals and Magazine of Natural History' in 1881. The names of Vejdovsky, who prefaced Potts's monograph with an account of the European species, and of Dybowsky, who published several important papers on cla.s.sification, should also be mentioned, while Weltner's catalogue of the known species (1895) is of the greatest possible value to students of the group.

Many authors have dealt with the physiology, reproduction and development of the Spongillidae, especially in recent years; Dr. R.

Evans's description of the larva of _Spongilla lacustris_ (1899), and his account of the development of the gemmule in _Ephydatia blembingia_ (1901), Zykoff's account of the development of the gemmule and of the sponge from the gemmule (1892), and Weltner's observations on colour and other points (1893, 1907), may be mentioned in particular. Laurent's observations on development (1844), which were published in the 'Voyage de la Bonite,' and especially the exquisite plates which accompany them, have not received the notice they deserve, probably on account of their method of publication.

LITERATURE.

The fullest account of the literature on the Spongillidae as yet published will be found in the first of Weltner's 'Spongillidenstudien'

(Archiv fur Naturgeschichte, lix (i), p. 209, 1893). Unfortunately it contains no references of later date than 1892. The following list is not a complete bibliography, but merely a list of books and papers that should prove of use to students of the Oriental Spongillidae.

(a) _Works of Reference._

1863. BOWERBANK, "A Monograph of the Spongillidae," P. Zool. Soc. London, 1863, pp. 440-472, pl. x.x.xviii.

1867. GRAY, J. E., "Notes on the arrangement of Sponges, with the description of some new genera." _ibid._ 1867, pp. 492-558.

1881. CARTER, "History and cla.s.sification of the known species of _Spongilla_," Ann. Nat. Hist. (5) vii, pp. 77-107, pls. v, vi.